Right bundle branch block induced by right ventricular involvement in inferior wall left ventricular acute myocardial infarction

Background: Cardiac resynchronization therapy has been shown to improve left ventricular performance in patients with left ventricular dysfunction and a left-sided interventricular conduction delay. This is performed by placing a pacing lead on the lateral left ventricular wall to stimulate the area normally stimulated by the left bundle branch. In patients with right bundle branch block (RBBB), pacing the right bundle branch could also result in resynchronization. Previous studies have shown that right ventricular outflow septal (RVOS) pacing does, in fact, utilize the native conduction system. Methods: 62 consecutive patients, 46 male/16 female, aged 75 +/− 10.5 yr, with RBBB and indications for pacing, underwent RVOS lead placement using commercially available pacing systems. The patients subsequently underwent bedside A-V optimization to achieve the narrowest QRS duration and most “normal” QRS complex. Echocardiography was performed to evaluate changes in wall motion comparing baseline with optimal pacing. Results: Baseline mean QRS duration 146 +/− 20.9 ms Optimized mean QRS duration 111 +/− 20.5 ms Average decrease in QRS duration -35 +/− 21.5 ms p < 0.001 Echocardiography demonstrated improvement in septal contraction abnormalities. Conclusions: 1) RVOS pacing in RBBB patients can significantly narrow the QRS complex on ECG. 2) Septal contraction abnormalities due to RBBB can be improved with RVOS pacing and optimal A-V timing. 3) Further studies are warranted to evaluate this therapy in a heart failure population.

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Impact on hospital mortality and morbidity of right ventricular involvement among patients with acute left ventricular infarction

Sao Paulo Medical Journal ◽

10.1590/s1516-31802006000400003 ◽

2006 ◽

Vol 124 (4) ◽

pp. 186-191 ◽

Cited By ~ 6

Author(s):

Afonso Celso Pereira ◽

Roberto Alexandre Franken ◽

Sandra Regina Schwarzwälder Sprovieri ◽

Valdir Golin

Keyword(s):

Myocardial Infarction ◽

Hospital Mortality ◽

Right Ventricular ◽

Left Ventricular ◽

Hospital Death ◽

Inferior Wall ◽

Mortality And Morbidity ◽

Killip Class ◽

Increased Risk ◽

The Impact

CONTEXT AND OBJECTIVE: There is uncertainty regarding the risk of major complications in patients with left ventricular (LV) infarction complicated by right ventricular (RV) involvement. The aim of this study was to evaluate the impact on hospital mortality and morbidity of right ventricular involvement among patients with acute left ventricular myocardial infarction. DESIGN AND SETTING: Prospective cohort study, at Emergency Care Unit of Hospital Central da Irmandade da Santa Casa de Misericórdia de São Paulo. METHODS: 183 patients with acute myocardial infarction participated in this study: 145 with LV infarction alone and 38 with both LV and RV infarction. The presence of complications and hospital death were compared between groups. RESULTS: 21% of the patients studied had LV + RV infarction. In this group, involvement of the dorsal and/or inferior wall was predominant on electrocardiogram (p < 0.0001). The frequencies of Killip class IV upon admission and 24 hours later were greater in the LV + RV group, along with electrical and hemodynamic complications, among others, and death. The probability of complications among the LV + RV patients was 9.7 times greater (odds ratio, OR = 9.7468; 95% confidence interval, CI: 2.8673 to 33.1325; p < 0.0001) and probability of death was 5.1 times greater (OR = 5.13; 95% CI: 2.2795 to 11.5510; p = 0.0001), in relation to patients with LV infarction alone. CONCLUSIONS: Patients with LV infarction with RV involvement present increased risk of early morbidity and mortality.

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